This invention relates to vacuum cleaner systems, and more particularly to a vacuum cleaner system having an electric powerhead which includes an airflow recirculation path for providing a cooling airflow over a beater brush motor.
Vacuum cleaners typically include a main motor which has a fan attached to an output shaft thereof for creating a suction airflow through an intake port. The suction airflow travels through a filter assembly and is exhausted through an exhaust outlet on the housing. Such vacuum cleaners also typically include a beater brush assembly which is driven rotationally by a separate beater brush motor. The beater brush motor is often disposed in a forward end of the housing.
Various attempts have been made to devise means for cooling the beater brush motor with varying degrees of success. One specific arrangement is shown in U.S. Pat. No. 5,638,575, and assigned to Techtronic, Ind. The cooling arrangement disclosed in this patent relies on drawing ambient air in through an opening disposed near a compartment which houses the beater brush motor and relying on a venturi effect created by the suction airflow as it flows past an opening in the compartment. However, this arrangement appears to rely entirely on the venturi effect created by the suction airflow, with no assistance from the exhaust flow out of the main fan of the device.
It is therefore desirable to provide some form of cleaning arrangement for use with a vacuum cleaner which does not rely entirely on the venturi effect created by the main suction airflow flowing past the compartment which houses a beater brush motor.
The present invention is directed to a vacuum cleaner system having a closed loop airflow recirculation path for continuously directing a cooling airflow over a beater brush motor. In a preferred embodiment the vacuum cleaner system includes a housing having an electric motor with a fan driven by an output shaft of the motor. The suction airflow created by the fan draws in dust and dirt entrained air through an intake port of the housing and through a filter assembly. The filtered suction airflow is exhausted through an exhaust port of the housing generating exhaust airflow. However, a portion of the clean, exhaust airflow is diverted away from the exhaust port of the housing and through a secondary flow path within the housing to a compartment in which a beater brush motor is housed. This serves to pressurize the motor compartment with clean air. An outlet of the compartment is disposed adjacent to the intake port such that the main suction airflow flows past the outlet of the compartment, thus creating a venturi effect which also helps to draw the clean, cooling airflow over the beater brush motor.
The present invention thus does not rely entirely on the venturi effect created by the main suction airflow to draw in a cooling airflow into the beater brush compartment. When pressurizing the beater brush compartment with a portion of clean air produced by the fan, a significant degree of cooling is achieved for the beater brush motor.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.